The long term objective of this study is to elucidate critical features of avian fertilization by studying sperm-egg binding and fertilization. Current objectives are to: (a) characterize a protein [universal sperm egg binding protein; USEBP] which serves as a "sandwich bridge" between gametes in the initial steps of sperm-egg binding; and (b) test synthetic peptides to map the bioactive regions and 3-D features of USEBP. The same system appears to function in mammalian species as diverse as human, horse, pig, mouse and bull. MALDI-MS and MALDI-PSD-MS have been extremely useful to our program for the verification of structure of the 13 synthetic peptides prepared for use in these studies. Future experiments will utilize photoactivatable peptide derivatives of USEBP to characterize the gamete membrane receptors, found on sperm and the egg, which serve as the "bread" for interaction with USEBP. The facility will be used to characterize those adducts after they have been purified.